2 Unix SMB/CIFS implementation.
3 Samba utility functions
4 Copyright (C) Andrew Tridgell 1992-1998
5 Copyright (C) Luke Kenneth Caseson Leighton 1998-1999
6 Copyright (C) Jeremy Allison 1999
7 Copyright (C) Stefan (metze) Metzmacher 2002
8 Copyright (C) Simo Sorce 2002
9 Copyright (C) Jim McDonough <jmcd@us.ibm.com> 2005
11 This program is free software; you can redistribute it and/or modify
12 it under the terms of the GNU General Public License as published by
13 the Free Software Foundation; either version 3 of the License, or
14 (at your option) any later version.
16 This program is distributed in the hope that it will be useful,
17 but WITHOUT ANY WARRANTY; without even the implied warranty of
18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19 GNU General Public License for more details.
21 You should have received a copy of the GNU General Public License
22 along with this program. If not, see <http://www.gnu.org/licenses/>.
28 * Some useful sids, more well known sids can be found at
29 * http://support.microsoft.com/kb/243330/EN-US/
33 const DOM_SID global_sid_World_Domain = /* Everyone domain */
34 { 1, 0, {0,0,0,0,0,1}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
35 const DOM_SID global_sid_World = /* Everyone */
36 { 1, 1, {0,0,0,0,0,1}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
37 const DOM_SID global_sid_Creator_Owner_Domain = /* Creator Owner domain */
38 { 1, 0, {0,0,0,0,0,3}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
39 const DOM_SID global_sid_NT_Authority = /* NT Authority */
40 { 1, 0, {0,0,0,0,0,5}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
41 const DOM_SID global_sid_System = /* System */
42 { 1, 1, {0,0,0,0,0,5}, {18,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
43 const DOM_SID global_sid_NULL = /* NULL sid */
44 { 1, 1, {0,0,0,0,0,0}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
45 const DOM_SID global_sid_Authenticated_Users = /* All authenticated rids */
46 { 1, 1, {0,0,0,0,0,5}, {11,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
48 /* for documentation */
49 const DOM_SID global_sid_Restriced = /* Restriced Code */
50 { 1, 1, {0,0,0,0,0,5}, {12,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
52 const DOM_SID global_sid_Network = /* Network rids */
53 { 1, 1, {0,0,0,0,0,5}, {2,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
55 const DOM_SID global_sid_Creator_Owner = /* Creator Owner */
56 { 1, 1, {0,0,0,0,0,3}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
57 const DOM_SID global_sid_Creator_Group = /* Creator Group */
58 { 1, 1, {0,0,0,0,0,3}, {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
59 const DOM_SID global_sid_Anonymous = /* Anonymous login */
60 { 1, 1, {0,0,0,0,0,5}, {7,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
62 const DOM_SID global_sid_Builtin = /* Local well-known domain */
63 { 1, 1, {0,0,0,0,0,5}, {32,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
64 const DOM_SID global_sid_Builtin_Administrators = /* Builtin administrators */
65 { 1, 2, {0,0,0,0,0,5}, {32,544,0,0,0,0,0,0,0,0,0,0,0,0,0}};
66 const DOM_SID global_sid_Builtin_Users = /* Builtin users */
67 { 1, 2, {0,0,0,0,0,5}, {32,545,0,0,0,0,0,0,0,0,0,0,0,0,0}};
68 const DOM_SID global_sid_Builtin_Guests = /* Builtin guest users */
69 { 1, 2, {0,0,0,0,0,5}, {32,546,0,0,0,0,0,0,0,0,0,0,0,0,0}};
70 const DOM_SID global_sid_Builtin_Power_Users = /* Builtin power users */
71 { 1, 2, {0,0,0,0,0,5}, {32,547,0,0,0,0,0,0,0,0,0,0,0,0,0}};
72 const DOM_SID global_sid_Builtin_Account_Operators = /* Builtin account operators */
73 { 1, 2, {0,0,0,0,0,5}, {32,548,0,0,0,0,0,0,0,0,0,0,0,0,0}};
74 const DOM_SID global_sid_Builtin_Server_Operators = /* Builtin server operators */
75 { 1, 2, {0,0,0,0,0,5}, {32,549,0,0,0,0,0,0,0,0,0,0,0,0,0}};
76 const DOM_SID global_sid_Builtin_Print_Operators = /* Builtin print operators */
77 { 1, 2, {0,0,0,0,0,5}, {32,550,0,0,0,0,0,0,0,0,0,0,0,0,0}};
78 const DOM_SID global_sid_Builtin_Backup_Operators = /* Builtin backup operators */
79 { 1, 2, {0,0,0,0,0,5}, {32,551,0,0,0,0,0,0,0,0,0,0,0,0,0}};
80 const DOM_SID global_sid_Builtin_Replicator = /* Builtin replicator */
81 { 1, 2, {0,0,0,0,0,5}, {32,552,0,0,0,0,0,0,0,0,0,0,0,0,0}};
82 const DOM_SID global_sid_Builtin_PreWin2kAccess = /* Builtin pre win2k access */
83 { 1, 2, {0,0,0,0,0,5}, {32,554,0,0,0,0,0,0,0,0,0,0,0,0,0}};
85 const DOM_SID global_sid_Unix_Users = /* Unmapped Unix users */
86 { 1, 1, {0,0,0,0,0,22}, {1,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
87 const DOM_SID global_sid_Unix_Groups = /* Unmapped Unix groups */
88 { 1, 1, {0,0,0,0,0,22}, {2,0,0,0,0,0,0,0,0,0,0,0,0,0,0}};
90 /* Unused, left here for documentary purposes */
92 #define SECURITY_NULL_SID_AUTHORITY 0
93 #define SECURITY_WORLD_SID_AUTHORITY 1
94 #define SECURITY_LOCAL_SID_AUTHORITY 2
95 #define SECURITY_CREATOR_SID_AUTHORITY 3
96 #define SECURITY_NT_AUTHORITY 5
100 * An NT compatible anonymous token.
103 static DOM_SID anon_sid_array[3] =
104 { { 1, 1, {0,0,0,0,0,1}, {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}},
105 { 1, 1, {0,0,0,0,0,5}, {2,0,0,0,0,0,0,0,0,0,0,0,0,0,0}},
106 { 1, 1, {0,0,0,0,0,5}, {7,0,0,0,0,0,0,0,0,0,0,0,0,0,0}} };
107 NT_USER_TOKEN anonymous_token = { 3, anon_sid_array, SE_NONE };
109 static DOM_SID system_sid_array[1] =
110 { { 1, 1, {0,0,0,0,0,5}, {18,0,0,0,0,0,0,0,0,0,0,0,0,0,0}} };
111 NT_USER_TOKEN system_token = { 1, system_sid_array, SE_ALL_PRIVS };
113 /****************************************************************************
114 Lookup string names for SID types.
115 ****************************************************************************/
117 static const struct {
118 enum lsa_SidType sid_type;
120 } sid_name_type[] = {
121 {SID_NAME_USER, "User"},
122 {SID_NAME_DOM_GRP, "Domain Group"},
123 {SID_NAME_DOMAIN, "Domain"},
124 {SID_NAME_ALIAS, "Local Group"},
125 {SID_NAME_WKN_GRP, "Well-known Group"},
126 {SID_NAME_DELETED, "Deleted Account"},
127 {SID_NAME_INVALID, "Invalid Account"},
128 {SID_NAME_UNKNOWN, "UNKNOWN"},
129 {SID_NAME_COMPUTER, "Computer"},
131 {(enum lsa_SidType)0, NULL}
134 const char *sid_type_lookup(uint32 sid_type)
138 /* Look through list */
139 while(sid_name_type[i].sid_type != 0) {
140 if (sid_name_type[i].sid_type == sid_type)
141 return sid_name_type[i].string;
146 return "SID *TYPE* is INVALID";
149 /**************************************************************************
150 Create the SYSTEM token.
151 ***************************************************************************/
153 NT_USER_TOKEN *get_system_token(void)
155 return &system_token;
158 /******************************************************************
159 get the default domain/netbios name to be used when dealing
160 with our passdb list of accounts
161 ******************************************************************/
163 const char *get_global_sam_name(void)
165 if ((lp_server_role() == ROLE_DOMAIN_PDC) || (lp_server_role() == ROLE_DOMAIN_BDC)) {
166 return lp_workgroup();
168 return global_myname();
171 /*****************************************************************
172 Convert a SID to an ascii string.
173 *****************************************************************/
175 char *sid_to_fstring(fstring sidstr_out, const DOM_SID *sid)
177 char *str = sid_string_talloc(talloc_tos(), sid);
178 fstrcpy(sidstr_out, str);
183 /*****************************************************************
184 Essentially a renamed dom_sid_string from librpc/ndr with a
185 panic if it didn't work
187 This introduces a dependency on librpc/ndr/sid.o which can easily
188 be turned around if necessary
189 *****************************************************************/
191 char *sid_string_talloc(TALLOC_CTX *mem_ctx, const DOM_SID *sid)
193 char *result = dom_sid_string(mem_ctx, sid);
194 SMB_ASSERT(result != NULL);
198 /*****************************************************************
199 Useful function for debug lines.
200 *****************************************************************/
202 char *sid_string_dbg(const DOM_SID *sid)
204 return sid_string_talloc(debug_ctx(), sid);
207 /*****************************************************************
209 *****************************************************************/
211 char *sid_string_tos(const DOM_SID *sid)
213 return sid_string_talloc(talloc_tos(), sid);
216 /*****************************************************************
217 Convert a string to a SID. Returns True on success, False on fail.
218 *****************************************************************/
220 bool string_to_sid(DOM_SID *sidout, const char *sidstr)
224 /* BIG NOTE: this function only does SIDS where the identauth is not >= 2^32 */
227 if ((sidstr[0] != 'S' && sidstr[0] != 's') || sidstr[1] != '-') {
228 DEBUG(3,("string_to_sid: Sid %s does not start with 'S-'.\n", sidstr));
232 ZERO_STRUCTP(sidout);
234 /* Get the revision number. */
236 conv = (uint32) strtoul(p, &q, 10);
237 if (!q || (*q != '-')) {
238 DEBUG(3,("string_to_sid: Sid %s is not in a valid format.\n", sidstr));
241 sidout->sid_rev_num = (uint8) conv;
245 conv = (uint32) strtoul(q, &q, 10);
246 if (!q || (*q != '-')) {
247 DEBUG(0,("string_to_sid: Sid %s is not in a valid format.\n", sidstr));
250 /* identauth in decimal should be < 2^32 */
251 /* NOTE - the conv value is in big-endian format. */
252 sidout->id_auth[0] = 0;
253 sidout->id_auth[1] = 0;
254 sidout->id_auth[2] = (conv & 0xff000000) >> 24;
255 sidout->id_auth[3] = (conv & 0x00ff0000) >> 16;
256 sidout->id_auth[4] = (conv & 0x0000ff00) >> 8;
257 sidout->id_auth[5] = (conv & 0x000000ff);
260 sidout->num_auths = 0;
262 for(conv = (uint32) strtoul(q, &q, 10);
263 q && (*q =='-' || *q =='\0') && (sidout->num_auths < MAXSUBAUTHS);
264 conv = (uint32) strtoul(q, &q, 10)) {
265 sid_append_rid(sidout, conv);
274 DOM_SID *string_sid_talloc(TALLOC_CTX *mem_ctx, const char *sidstr)
276 DOM_SID *result = TALLOC_P(mem_ctx, DOM_SID);
281 if (!string_to_sid(result, sidstr))
287 /*****************************************************************
288 Add a rid to the end of a sid
289 *****************************************************************/
291 bool sid_append_rid(DOM_SID *sid, uint32 rid)
293 if (sid->num_auths < MAXSUBAUTHS) {
294 sid->sub_auths[sid->num_auths++] = rid;
300 bool sid_compose(DOM_SID *dst, const DOM_SID *domain_sid, uint32 rid)
302 sid_copy(dst, domain_sid);
303 return sid_append_rid(dst, rid);
306 /*****************************************************************
307 Removes the last rid from the end of a sid
308 *****************************************************************/
310 bool sid_split_rid(DOM_SID *sid, uint32 *rid)
312 if (sid->num_auths > 0) {
314 *rid = sid->sub_auths[sid->num_auths];
320 /*****************************************************************
321 Return the last rid from the end of a sid
322 *****************************************************************/
324 bool sid_peek_rid(const DOM_SID *sid, uint32 *rid)
329 if (sid->num_auths > 0) {
330 *rid = sid->sub_auths[sid->num_auths - 1];
336 /*****************************************************************
337 Return the last rid from the end of a sid
338 and check the sid against the exp_dom_sid
339 *****************************************************************/
341 bool sid_peek_check_rid(const DOM_SID *exp_dom_sid, const DOM_SID *sid, uint32 *rid)
343 if (!exp_dom_sid || !sid || !rid)
346 if (sid->num_auths != (exp_dom_sid->num_auths+1)) {
350 if (sid_compare_domain(exp_dom_sid, sid)!=0){
355 return sid_peek_rid(sid, rid);
358 /*****************************************************************
360 *****************************************************************/
362 void sid_copy(DOM_SID *dst, const DOM_SID *src)
368 dst->sid_rev_num = src->sid_rev_num;
369 dst->num_auths = src->num_auths;
371 memcpy(&dst->id_auth[0], &src->id_auth[0], sizeof(src->id_auth));
373 for (i = 0; i < src->num_auths; i++)
374 dst->sub_auths[i] = src->sub_auths[i];
377 /*****************************************************************
378 Write a sid out into on-the-wire format.
379 *****************************************************************/
381 bool sid_linearize(char *outbuf, size_t len, const DOM_SID *sid)
385 if (len < ndr_size_dom_sid(sid, NULL, 0))
388 SCVAL(outbuf,0,sid->sid_rev_num);
389 SCVAL(outbuf,1,sid->num_auths);
390 memcpy(&outbuf[2], sid->id_auth, 6);
391 for(i = 0; i < sid->num_auths; i++)
392 SIVAL(outbuf, 8 + (i*4), sid->sub_auths[i]);
397 /*****************************************************************
398 Parse a on-the-wire SID to a DOM_SID.
399 *****************************************************************/
401 bool sid_parse(const char *inbuf, size_t len, DOM_SID *sid)
409 sid->sid_rev_num = CVAL(inbuf, 0);
410 sid->num_auths = CVAL(inbuf, 1);
411 if (sid->num_auths > MAXSUBAUTHS) {
414 memcpy(sid->id_auth, inbuf+2, 6);
415 if (len < 8 + sid->num_auths*4)
417 for (i=0;i<sid->num_auths;i++)
418 sid->sub_auths[i] = IVAL(inbuf, 8+i*4);
422 /*****************************************************************
423 Compare the auth portion of two sids.
424 *****************************************************************/
426 static int sid_compare_auth(const DOM_SID *sid1, const DOM_SID *sid2)
437 if (sid1->sid_rev_num != sid2->sid_rev_num)
438 return sid1->sid_rev_num - sid2->sid_rev_num;
440 for (i = 0; i < 6; i++)
441 if (sid1->id_auth[i] != sid2->id_auth[i])
442 return sid1->id_auth[i] - sid2->id_auth[i];
447 /*****************************************************************
449 *****************************************************************/
451 int sid_compare(const DOM_SID *sid1, const DOM_SID *sid2)
462 /* Compare most likely different rids, first: i.e start at end */
463 if (sid1->num_auths != sid2->num_auths)
464 return sid1->num_auths - sid2->num_auths;
466 for (i = sid1->num_auths-1; i >= 0; --i)
467 if (sid1->sub_auths[i] != sid2->sub_auths[i])
468 return sid1->sub_auths[i] - sid2->sub_auths[i];
470 return sid_compare_auth(sid1, sid2);
473 int sid_compare_sort(const void *p1, const void *p2)
475 const struct dom_sid *sid1 = (const struct dom_sid *)p1;
476 const struct dom_sid *sid2 = (const struct dom_sid *)p2;
479 if (sid1->sid_rev_num != sid2->sid_rev_num) {
480 return sid1->sid_rev_num - sid2->sid_rev_num;
483 for (i = 0; i < 6; i++) {
484 if (sid1->id_auth[i] != sid2->id_auth[i]) {
485 return sid1->id_auth[i] - sid2->id_auth[i];
489 if (sid1->num_auths != sid2->num_auths) {
490 return sid1->num_auths - sid2->num_auths;
493 for (i = 0; i<sid1->num_auths; i++) {
494 if (sid1->sub_auths[i] != sid2->sub_auths[i]) {
495 return sid1->sub_auths[i] - sid2->sub_auths[i];
502 /*****************************************************************
503 See if 2 SIDs are in the same domain
504 this just compares the leading sub-auths
505 *****************************************************************/
507 int sid_compare_domain(const DOM_SID *sid1, const DOM_SID *sid2)
511 n = MIN(sid1->num_auths, sid2->num_auths);
513 for (i = n-1; i >= 0; --i)
514 if (sid1->sub_auths[i] != sid2->sub_auths[i])
515 return sid1->sub_auths[i] - sid2->sub_auths[i];
517 return sid_compare_auth(sid1, sid2);
520 /*****************************************************************
522 *****************************************************************/
524 bool sid_equal(const DOM_SID *sid1, const DOM_SID *sid2)
526 return sid_compare(sid1, sid2) == 0;
529 /*****************************************************************
530 Returns true if SID is internal (and non-mappable).
531 *****************************************************************/
533 bool non_mappable_sid(DOM_SID *sid)
539 sid_split_rid(&dom, &rid);
541 if (sid_equal(&dom, &global_sid_Builtin))
544 if (sid_equal(&dom, &global_sid_NT_Authority))
550 /*****************************************************************
551 Return the binary string representation of a DOM_SID.
553 *****************************************************************/
555 char *sid_binstring(const DOM_SID *sid)
558 int len = ndr_size_dom_sid(sid, NULL, 0);
559 buf = (char *)SMB_MALLOC(len);
562 sid_linearize(buf, len, sid);
563 s = binary_string_rfc2254(buf, len);
568 /*****************************************************************
569 Return the binary string representation of a DOM_SID.
571 *****************************************************************/
573 char *sid_binstring_hex(const DOM_SID *sid)
576 int len = ndr_size_dom_sid(sid, NULL, 0);
577 buf = (char *)SMB_MALLOC(len);
580 sid_linearize(buf, len, sid);
581 s = binary_string(buf, len);
586 /*******************************************************************
587 Tallocs a duplicate SID.
588 ********************************************************************/
590 DOM_SID *sid_dup_talloc(TALLOC_CTX *ctx, const DOM_SID *src)
597 if((dst = TALLOC_ZERO_P(ctx, DOM_SID)) != NULL) {
604 /********************************************************************
605 Add SID to an array SIDs
606 ********************************************************************/
608 NTSTATUS add_sid_to_array(TALLOC_CTX *mem_ctx, const DOM_SID *sid,
609 DOM_SID **sids, size_t *num)
611 *sids = TALLOC_REALLOC_ARRAY(mem_ctx, *sids, DOM_SID,
615 return NT_STATUS_NO_MEMORY;
618 sid_copy(&((*sids)[*num]), sid);
625 /********************************************************************
626 Add SID to an array SIDs ensuring that it is not already there
627 ********************************************************************/
629 NTSTATUS add_sid_to_array_unique(TALLOC_CTX *mem_ctx, const DOM_SID *sid,
630 DOM_SID **sids, size_t *num_sids)
634 for (i=0; i<(*num_sids); i++) {
635 if (sid_compare(sid, &(*sids)[i]) == 0)
639 return add_sid_to_array(mem_ctx, sid, sids, num_sids);
642 /********************************************************************
643 Remove SID from an array
644 ********************************************************************/
646 void del_sid_from_array(const DOM_SID *sid, DOM_SID **sids, size_t *num)
648 DOM_SID *sid_list = *sids;
651 for ( i=0; i<*num; i++ ) {
653 /* if we find the SID, then decrement the count
654 and break out of the loop */
656 if ( sid_equal(sid, &sid_list[i]) ) {
662 /* This loop will copy the remainder of the array
663 if i < num of sids ni the array */
665 for ( ; i<*num; i++ )
666 sid_copy( &sid_list[i], &sid_list[i+1] );
671 bool add_rid_to_array_unique(TALLOC_CTX *mem_ctx,
672 uint32 rid, uint32 **pp_rids, size_t *p_num)
676 for (i=0; i<*p_num; i++) {
677 if ((*pp_rids)[i] == rid)
681 *pp_rids = TALLOC_REALLOC_ARRAY(mem_ctx, *pp_rids, uint32, *p_num+1);
683 if (*pp_rids == NULL) {
688 (*pp_rids)[*p_num] = rid;
693 bool is_null_sid(const DOM_SID *sid)
695 static const DOM_SID null_sid = {0};
696 return sid_equal(sid, &null_sid);
699 bool is_sid_in_token(const NT_USER_TOKEN *token, const DOM_SID *sid)
703 for (i=0; i<token->num_sids; i++) {
704 if (sid_compare(sid, &token->user_sids[i]) == 0)
710 NTSTATUS sid_array_from_info3(TALLOC_CTX *mem_ctx,
711 const struct netr_SamInfo3 *info3,
713 size_t *num_user_sids,
714 bool include_user_group_rid,
715 bool skip_ressource_groups)
719 DOM_SID *sid_array = NULL;
723 if (include_user_group_rid) {
724 if (!sid_compose(&sid, info3->base.domain_sid, info3->base.rid)) {
725 DEBUG(3, ("could not compose user SID from rid 0x%x\n",
727 return NT_STATUS_INVALID_PARAMETER;
729 status = add_sid_to_array(mem_ctx, &sid, &sid_array, &num_sids);
730 if (!NT_STATUS_IS_OK(status)) {
731 DEBUG(3, ("could not append user SID from rid 0x%x\n",
737 if (!sid_compose(&sid, info3->base.domain_sid, info3->base.primary_gid)) {
738 DEBUG(3, ("could not compose group SID from rid 0x%x\n",
739 info3->base.primary_gid));
740 return NT_STATUS_INVALID_PARAMETER;
742 status = add_sid_to_array(mem_ctx, &sid, &sid_array, &num_sids);
743 if (!NT_STATUS_IS_OK(status)) {
744 DEBUG(3, ("could not append group SID from rid 0x%x\n",
749 for (i = 0; i < info3->base.groups.count; i++) {
750 /* Don't add the primary group sid twice. */
751 if (info3->base.primary_gid == info3->base.groups.rids[i].rid) {
754 if (!sid_compose(&sid, info3->base.domain_sid,
755 info3->base.groups.rids[i].rid)) {
756 DEBUG(3, ("could not compose SID from additional group "
757 "rid 0x%x\n", info3->base.groups.rids[i].rid));
758 return NT_STATUS_INVALID_PARAMETER;
760 status = add_sid_to_array(mem_ctx, &sid, &sid_array, &num_sids);
761 if (!NT_STATUS_IS_OK(status)) {
762 DEBUG(3, ("could not append SID from additional group "
763 "rid 0x%x\n", info3->base.groups.rids[i].rid));
768 /* Copy 'other' sids. We need to do sid filtering here to
769 prevent possible elevation of privileges. See:
771 http://www.microsoft.com/windows2000/techinfo/administration/security/sidfilter.asp
774 for (i = 0; i < info3->sidcount; i++) {
776 if (skip_ressource_groups &&
777 (info3->sids[i].attributes & SE_GROUP_RESOURCE)) {
781 status = add_sid_to_array(mem_ctx, info3->sids[i].sid,
782 &sid_array, &num_sids);
783 if (!NT_STATUS_IS_OK(status)) {
784 DEBUG(3, ("could not add SID to array: %s\n",
785 sid_string_dbg(info3->sids[i].sid)));
790 *user_sids = sid_array;
791 *num_user_sids = num_sids;